The geometrical factor of infinitely long cylindrical ICR cells for collision energy-resolved mass spectrometry: Appearance energies of EI(2)(+) (E=P, As, Sb, and Bi) from collision-induced dissociation of EI(3)(+center dot) and [EI(2)center dot ligand](+) complexes

The geometrical factor beta of infinitely long cylindrical ICR cells is determined to employ collision energy-resolved mass spectrometry (CERMS) with a FT-ICR spectrometer. In case of four identical infinitely long cylindrical electrodes beta equals 0.90. A cylindrical ICR cell emulating infinitely long electrodes is used to study the energy-dependent collision-induced dissociation (CID) of EI(3)(+) radical cations and [EI(2) . ligand](+) complexes with E = P, As, Sb, and Bi and ligands benzene, propene and acetone. In the low collision energy regime the EI(3)(+) precursor ions decompose by loss of I-. and the [EI(2) . ligand](+) exclusively by breaking the EI(2)(+)-ligand bond and formation of EI(2)(+). Appearance energies A(EI(2)(+)) of EI(2)(+) generated from EI(3)(+) are A(PI2+) = 1.88 ev, A(AsI2+) = 1.15 eV, A(SbI2+) = 1.22 eV, and A(BiI2+ = 0.78 eV. Fission of the EI(2)-ligand bond requires collision energies ranging from 1.88 eV in case of [PI2 . acetone](+) down to 0.86 eV if [BiI2 . benzene](+) is studied. Appearance energy measurements of well characterized dissociations indicate an accuracy better than +/- 0.20 eV.